Supplemental elastic stiffness to reduce isolator displacements for seismic-isolated bridges in near-fault zones

Date

2007-01-01

Author

Dicleli, Murat

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In this paper, the efficiency of providing supplemental elastic stiffness to seismic-isolated bridges (SIBs) for reducing the isolator displacements while keeping the substructure forces in reasonable ranges is investigated. Conventional supplemental elastic devices (SEDs) such as elastomeric bearings placed in parallel with seismic isolators between the superstructure and substructures are used for this purpose. A parametric study, involving more than 400 nonlinear time history (NLTH) analyses of realistic and simplified structural models of typical SIBs are conducted using simulated and actual NF ground motions to investigate the applicability of the proposed solution. It is found that providing SEDs is beneficial in reducing the isolator forces to manageable ranges for SIBs subjected to NF ground motions with moderate to large magnitudes regardless of the distance from the fault. It is also found that the stiffness of the SED may be chosen in relation to the velocity pulse period (or magnitude) of the NF ground motion to minimize the isolator displacements by avoiding resonant response. Further analyses conducted using a realistic structural model of an existing bridge and five NF earthquakes with moderate to large magnitudes confirmed that SEDs may be used to reduce the displacement of the isolators while keeping the substructure base shear forces in reasonable ranges for SIBs located in NF zones. c 2006 Elsevier Ltd. All rights reserved.

Subject Keywords

Force, Displacement, Damper, Stiffness, Design, Near fault, Nonlinear response, Seismic isolation

URI

https://hdl.handle.net/11511/81003
https://d1wqtxts1xzle7.cloudfront.net/52432763/Supplemental_elastic_stiffness_to_reduce20170402-23334-zp22db.pdf?1491149108=&response-content-disposition=inline%3B+filename%3DSupplemental_elastic_stiffness_to_reduce.pdf&Expires=1612003194&Signature=gvy-3kbLbqQ7Law2vNVZ7kKuvPWksbpVvIj-pSUbnuMucS7smIpc~BRCeHSKENpNwB2LqHVHHWDs4ld4p0UDB~HAFNa6kEpUJiM2XioEHsaHL2hZ4iFcLx~EXN6~IElvoh6xgP8Qi5Mf7TQTL-nd2LU4xXdVmYvg4yNn~7RUSQkaSIx6rENdG5ARWoBEyboStF~CQ7YzZEaNh5wRiLAciD9o31R9xYSDLoScj~KWr1NuPFnd2Sejs0x80RehLzI3OggK~5ddb8Ny5vYAy4q2c82x4pcCMTrm-mBIEYyQDXlN2sPYzAWA6AZHGfRLtz5OiK9wm6Codj1YjVqBAKc1ig__&Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA

Conference Name

Proc. 86th Annual Meeting (on CD- ROM), Washington, D. C., USA, Transportation Research Board, Federal Highway Administration

Collections

Department of Engineering Sciences, Conference / Seminar

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Supplemental elastic stiffness to reduce isolator displacements for seismic-isolated bridges in near-fault zones Dicleli, Murat (2007-05-01) In this paper, the efficiency of providing supplemental elastic stiffness to seismic-isolated bridges (SIBs) for reducing the isolator displacements while keeping the substructure forces in reasonable ranges is investigated. Conventional supplemental elastic devices (SEDs) such as elastomeric bearings placed in parallel with seismic isolators between the superstructure and substructures are used for this purpose. A parametric study, involving more than 400 nonlinear time history (NLTH) analyses of realistic...
Performance of seismic-isolated bridges with and without elastic-gap devices in near-fault zones Dicleli, Murat (2008-05-01) In this paper, the efficiency of providing elastic-gap devices (EGDs) to improve the performance of seismic- isolated bridges (SIBs) in near-fault (NF) zones is investigated. The device is primarily made of an assembly of circular rubber bearings and steel plates to provide additional elastic stiffness to the SIB upon closure of a gap. The EDG is intended to function at two performance levels under service and maximum considered design level (MCDL) NF earthquakes to reduce isolator displacements while keepi...
Optimal Isolator Parameters for Economical Mitigation of Seismic Risk for Highway Bridges Dicleli, Murat (null; 2009-06-28) In this study, closed form equations as functions of the isolator, bridge and ground motion properties are formulated to calculate the optimum characteristic strength, Qd and post-elastic stiffness, k d, of the isolator to minimize the maximum isolator displacement (MID) and force (MIF) for seismic isolated bridges (SIBs). This formulation required more than 13000 nonlinear time history analyses of simplified SIB models. The analyses results revealed that the optimum Qd and k d are highly dependent on the s...
Equivalent linear analysis of seismic-isolated bridges subjected to near-fault ground motions with forward rupture directivity effect Dicleli, Murat (2007-01-01) This study encompasses the assessment of the equivalent linear (EL) analysis procedure for the design of seismic isolated bridges (SIB) subjected to near-fault ground motions with forward rupture directivity effect. The assessment procedure involves the comparison of the seismic response quantities obtained from EL analyses with those obtained from nonlinear time history (NLTH) analyses. The effect of several isolator and near-fault ground motion properties are considered in the assessment of the EL analysi...
Optimum Properties of Seismic Isolation Systems in Highway Bridges to Minimize Isolator Displacements or Substructure Forces Dicleli, Murat (null; 2019-07-06) In this study, closed form equations as functions of the isolator, bridge and ground motion properties are formulated to calculate the optimum characteristic strength, Qd and post-elastic stiffness, kd, of the isolator to minimize the maximum isolator displacement (MID) and force (MIF) for seismic isolated bridges (SIBs). For this purpose, first, sensitivity analyses are conducted to identify the bridge, isolator and ground motion parameters that affect the optimum values of Qd and kd. Next, for the identif...

Citation Formats

M. Dicleli, “Supplemental elastic stiffness to reduce isolator displacements for seismic-isolated bridges in near-fault zones,” Washington, Amerika Birleşik Devletleri, 2007, p. 1, Accessed: 00, 2021. [Online]. Available: https://hdl.handle.net/11511/81003.